JP2003267691A - Forklift truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo handling vehicle that can structurally ensure safety during travel irrespective of the driving skill of an operator. <P>SOLUTION: The cargo handling vehicle comprises distance sensors 2 to 4 mounted in different height positions to detect distances to measured points on a travel road surface F ahead of the vehicle, and a controller 5 for limiting the operation of a traveling motor 6 if the heights H1 to H3 of the mounting positions of the distance sensors 2 to 4 and the detected distances L1 to L3 detected by the distance sensors 2 to 4 break a proportional relation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling vehicle, and more particularly to a technique for ensuring safety during traveling.

[0002]

2. Description of the Related Art A conventional forklift truck, which is a kind of cargo handling vehicle used for cargo handling work, has an overall structure as shown in FIG. That is, the forklift 21 includes a vehicle body 22 in which a traveling / steering device that executes a traveling operation and a steering operation, a hydraulic device (not shown) that executes a lift (elevating) operation, and the like are incorporated. A driver's seat 23 is provided at the center of the main body 22. A control device 24 including a microcomputer or the like is built in the rear portion of the vehicle body 22, and the control device 24 includes a traveling motor that constitutes a traveling / steering device and a hydraulic motor that constitutes a hydraulic device. Controls the operation as a whole.

A pair of left and right masts 25 are provided upright on the front part of the vehicle body 22, and the lifting and lowering operation of the fork 26 is guided by these masts 25. Further, at the rear portion of the vehicle body 22, a counterweight 27 is provided for counteracting a forward rotation moment generated when a load is placed on the fork 26.

Reference numeral 28 in FIG. 5 is a backrest,
Reference numeral 29 denotes a head card, and the backrest 28 has a load placed on the fork 26 on the rear side, that is, the vehicle body 2
The head card 29 protects the operator from a load or the like that drops from above toward the driver's seat 23.

[0005]

By the way, conventionally, forklifts have been used in various cargo handling operations, and are also utilized in freight stations and freight terminals in rail transportation and truck transportation. At cargo terminals, etc., the floor surface of the loading / unloading area is set high in advance to correspond to the height of the truck bed, and a forklift that runs on the floor of the loading / unloading area by the operator's operation. Is used to unload and load trucks.

However, when the conventional forklift 21 as shown in FIG. 5 is used, when the load is placed on the fork 26, the load obstructs the field of view of the operator on the driver's seat 23 on the vehicle body 22. Therefore, it may not be possible to secure sufficient visibility. Then, in such a state, the operator may mistakenly operate the vehicle, and as a result, the forklift 21 passes through a step from the floor surface such as the cargo handling field, which is the traveling road surface, that is, a truck surface, that is, a truck. There is a risk that they will fall on the road surface.

In particular, when an operator who is inexperienced in driving skills is driving, it is difficult to stop the forklift 21 well before the step, so that there is a problem that the forklift 21 may fall down. It was

The present invention was devised in view of such inconveniences, and an object of the present invention is to provide a forklift having a structure capable of ensuring safety during traveling regardless of the operator's driving skill. I am trying.

[0009]

In order to achieve the above object, the invention of claim 1 is a cargo handling vehicle having a vehicle body for carrying out cargo handling work and a drive means for driving the vehicle body to travel. Measuring means for measuring a distance between the vehicle body and a point on the road surface which is separated from the vehicle body by a predetermined distance;
A plurality of control units are provided so that the distances are different from each other, and a control unit is provided to control the driving unit so as to limit the traveling operation when the distance measured by each measuring unit fluctuates. There is.

According to this structure, when the cargo handling vehicle approaches the step and the distance measured by each measuring means fluctuates, the drive means is controlled by the control means so as to limit the traveling operation. Therefore, it is possible to prevent the cargo handling vehicle from falling from the step.

The invention according to claim 2 is the invention according to claim 1, further comprising a speed detecting means for detecting a traveling speed of the vehicle body, wherein the control means travels in a measuring direction of the measuring means. The driving means is controlled so that the traveling speed at the time of carrying out is equal to or less than a predetermined value.

According to this structure, the drive means is controlled by the control means so that the traveling operation in the measuring direction of the measuring means is performed at a traveling speed equal to or lower than a predetermined value, so that the vehicle travels at a traveling speed exceeding the predetermined value. Even if it does, the traveling speed is reduced to the above-mentioned predetermined value when the distance measured by each measuring means changes. Therefore, the cargo handling vehicle slowly approaches the step, and the risk of falling can be reduced. Further, when the above-mentioned predetermined value is zero, the cargo handling vehicle cannot travel toward the step, and the risk of falling can be eliminated. Such limitation of the traveling speed is to limit the traveling operation.
Here, since the traveling operation of the cargo handling vehicle in the direction opposite to the measuring direction of the measuring means, that is, the direction away from the step is not limited, the operator can move the cargo handling vehicle away from the step as needed.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the measuring means are provided at different height positions of the vehicle body on the same plane perpendicular to the road surface. The distance measuring directions are provided so as to be parallel to each other, and the control means controls the driving means based on a relationship between a height of a mounting position of the measuring means and the distance measured by the measuring means. Is characterized by.

According to this structure, the measuring means are mounted at different height positions of the vehicle body so that the detection directions are parallel to each other on the same plane perpendicular to the road surface. When the cargo handling vehicle travels on a flat road surface, a proportional relationship is established between the height of the mounting position of the measuring means and the distance to the point on the road surface detected by the measuring means. When the relationship is not established, it can be determined that there is a step somewhere on the road surface detected by the measuring means. Then, by controlling the drive means by the control device based on this relationship to limit the traveling operation, it is possible to prevent the cargo handling vehicle from approaching a step or falling.

According to a fourth aspect of the present invention, there is provided a cargo handling vehicle having a vehicle body for carrying out cargo handling work and a drive means for driving the vehicle body to travel, wherein the vehicle body and a road surface separated from the vehicle body by a predetermined distance. A plurality of measuring means for measuring the distance to the upper point are provided so that the distances are different from each other, and when the distance measured by each measuring means fluctuates, the vehicle is mounted on the vehicle body. It is characterized by providing an alarm means for issuing an alarm to an existing operator.

With such a structure, when the cargo handling vehicle approaches the step and the distance measured by each measuring means changes, the warning means gives an alarm to the operator, so that the cargo handling can be carried out to the operator. It can alert you to a fall by notifying you that the vehicle is approaching a step.

A fifth aspect of the present invention is the cargo handling vehicle according to any one of the first to fourth aspects, wherein the front part of the vehicle body is provided with a vertically movable fork and the measuring means is the fork. It is provided so as to measure the distance to a point on the road surface in front of the tip of the.

According to this structure, since the measuring means detects the distance from the vehicle body to the point on the road surface in front of the tip of the fork, there is a case where there is a step in front of the tip of the fork. However, the presence or absence of a step can be determined based on the distance to the road surface detected by the measuring means. Further, when the measuring means is arranged so as to detect the distance to a point on the road surface relatively close to the vehicle body, even if the running operation is stopped after it is determined that there is a step, it is completely stopped. Since a certain amount of stop distance is required before the cargo handling, the cargo handling vehicle may fall without being stopped, but with such a configuration, the point on the road surface detected by the measuring means is a fork. Since it is ahead of the tip of, there is no such concern.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a counterbalance type forklift, which is a type of cargo handling vehicle, will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a simplified overall structure of a forklift according to the present embodiment, FIG. 2 is an explanatory view schematically showing a side structure of the forklift, and FIG. 3 is a function showing a simplified control system of the forklift. FIG. 4 is a block diagram, and FIG. 4 is an explanatory view schematically showing a traveling state of the forklift. In FIG. 1, the same parts and portions as those of the conventional forklift shown in FIG. 5 are designated by the same reference numerals.

The forklift 1 according to the present embodiment is
As shown in FIG. 1 and FIG. 2, the vehicle main body 22 is provided with a traveling / steering device for executing traveling and steering operations, a hydraulic device (not shown) for performing lifting operations, and the like. A pair of masts 25 that guide the up-and-down movement of the fork 26 are erected on the front part of the vehicle body 22. The masts 25 on the outer side of the one side of the mast 25 have different height positions on the front side of the vehicle. Three distance sensors 2 for detecting the distance to a point on the traveling road surface F of
3 and 4 are attached. These distance sensors 2, 3 and 4 are the measuring means in the present invention, and as the distance sensor,
For example, an ultrasonic distance sensor or an optical distance sensor can be used. Reference numeral 28 in FIG. 1 is a backrest, and 29 is a head card.

As shown in FIG. 2, the distance sensors 2, 3, 4
Are installed so that they are installed in the same posture, that is, the detection directions of the distance sensors 2, 3 and 4 are obliquely downward and forward and are parallel to each other on the same plane perpendicular to the traveling road surface F. Therefore, the angles formed by the detection directions of the distance sensors 2, 3, 4 and the traveling road surface F are the same angle θ. In this embodiment, the distance sensor 2 is attached at the highest position, the distance sensor 3 is attached at the next highest position, and the distance sensor 4 is attached at the lowest position.

By the way, the heights from the traveling road surface F at the positions where the distance sensors 2, 3 and 4 are attached are H1 and H, respectively.
2 and H3, and the distances to the measurement points on the traveling road surface F detected by the respective distance sensors 2, 3 and 4 (hereinafter referred to as detection distances) are L1, L2 and L3, as shown in FIG. In addition, the detection distances L1, L2, L3 by the respective distance sensors
Is the hypotenuse length, and measurement is performed by the distance sensors 2, 3, 4 on the traveling road surface F from the intersection of the perpendicular line drawn from the mounting position of each distance sensor 2, 3, 4 to the traveling road surface F and the traveling road surface F. Three triangles having a base length up to the point and other side heights H1, H2, and H3 of each distance sensor are hypothesized. At this time, the angles formed by the detection directions of the distance sensors 2, 3, 4 and the traveling road surface F are the same angle θ, and the distance sensors 2, 3, 4 are on the outer surface of the same mast 25. Since the three triangles are attached to each other, the three triangles have a similar relationship, and H1: H2: H3 = L1: L
2: The proportional relationship of L3 is established.

As shown in FIG. 1, a counterweight 27 is provided at the rear of the vehicle body 22, and a control device 5 as a control means according to the present invention, which is composed of a microcomputer or the like, is built in the counterweight 27. Has been done. The control device 5 is supposed to control a traveling motor 6 included in the traveling / steering device as described later. Here, the traveling motor 6 is the driving means in the present invention. Further, a speed sensor 9 as a speed detecting means composed of a rotary encoder is attached to the rotary shaft of the traveling motor 6, and the rotational speed of the traveling motor 6 is converted into the traveling speed V of the forklift 1 to be detected. ing. The traveling speed V is detected as a positive value in the forward direction of the forklift 1 and a negative value in the reverse direction.

The control unit 5, as shown in FIG.
It has a CPU 7 having a judgment processing function and a memory 8 having a data storage function. The distance sensors 2, 3, 4 are connected to the input side of the CPU 7, the detection distances L1, L2, L3 detected by the distance sensors are input, and the speed sensor 9 is connected to the forklift 1.
The traveling speed V of is input. On the other hand, a traveling motor 6 which constitutes a traveling / steering device is connected to the output side of the CPU 7. Further, the heights H1, H2, H3 of the respective mounting positions of the distance sensors 2, 3, 4 and the speed limits Va, Vb (<Va) of the forklift 1 are stored in the memory 8 in advance as data, and the CPU 7 Reads out these data and performs the processing described in detail below.

The CPU 7 detects the detection distances L1, L2 and L3 detected by the distance sensors 2, 3 and 4, and the memory 8
H based on the heights H1, H2, H3 stored in
The relationship of 1: H2: H3 and L1: L2: L3 is calculated by calculation, and H1: H2: H3 = L1: L2: L.
Processing for determining whether or not the proportional relationship of 3 is established is performed. When the CPU 7 determines that the above proportional relationship is not established, the CPU 7 compares the current traveling speed V detected by the speed sensor 9 with the speed limits Va and Vb stored in the memory 8. Then, the traveling motor 6 is controlled so that the traveling speed V becomes equal to or lower than the speed limits Va and Vb.

First, as shown in FIG. 4A, although the forklift 1 is approaching the step D, all the distance sensors 2, 3 and 4 detect the distance to the measurement point on the traveling road surface F. If it is, H1: H2: H3 = L1:
L2: L3 is established, and the CPU 7 determines that the proportional relationship is established. Therefore, C
The PU 7 continues to drive the traveling motor 6 as it is, and the traveling operation of the forklift 1 is not limited at all.

However, as shown in FIG. 4B, since the forklift 1 approaches the step D, the distance sensors 3 and 4 detect the distance to the measurement point on the traveling road surface F, but the distance sensor In the case where 2 detects the distance to the measurement point on the traveling road surface G on which the truck or the like below the step D travels, the detection distance L1 detects the distance to the measurement point on the traveling road surface F. Also becomes longer. Therefore, H2: H3 = L2: L3 holds, but H1: H
2: H3 ≠ L1: L2: L3, and the distance sensors 3 and 4
However, the CPU 7 determines that the proportional relationship for the distance sensor 2 is not established.

Therefore, the CPU 7 compares the current running speed V detected by the speed sensor 9 with the speed limit Va (for example, 2 km / h) stored in the memory 8 to limit the running speed V. The traveling motor 6 is controlled so that the speed becomes equal to or lower than the speed Va. That is, when the traveling speed V of the forklift 1 exceeds the speed limit Va, the CPU 7
Reduces the rotational speed of the traveling motor 6 to reduce the traveling speed V of the forklift 1 to the speed limit Va. In addition, the forklift 1 travels at a traveling speed exceeding the speed limit Va.
Even if an acceleration operation is attempted to drive
The PU 7 stops accelerating up to the speed limit Va, and the traveling speed V
The traveling motor 6 is controlled so that is maintained below the speed limit Va. .

Furthermore, as shown in FIG. 4C, when the forklift 1 approaches the step D further, the distance sensors 2 and 3 detect the distance to the measurement point on the traveling road surface G. Only the distance sensor 4 detects the distance to the measurement point on the traveling road surface F on which the forklift 1 travels, and the distances L1 and L detected by the distance sensors 2 and 3 are detected.
Both 2 are longer than the case where the distance to the measurement point on the traveling road surface F is detected. Therefore, H1: H2 ≠ L1: L
2, and H1: H2: H3 ≠ L1: L2: L3. Therefore, the CPU 7 determines that the proportional relationship regarding the distance sensor 4 that detects the distance to the traveling road surface F is not established.

Therefore, the CPU 7 compares the current running speed V detected by the speed sensor 9 with the speed limit Vb (for example, 0 km / h) stored in the memory 8 to limit the running speed V. The traveling motor 6 is controlled so that the speed becomes equal to or lower than the speed Vb. That is, the rotation of the traveling motor 6 in the forward direction of the forklift 1 is stopped by the CPU 7,
The forklift 1 will stop. At this time, traveling at a traveling speed less than the speed limit Vb, that is, backward movement of the forklift 1 is possible.

As described above, in the present embodiment,
When the CPU 7 determines that the proportional relationship related to the distance sensors 3 and 4 is established but the proportional relationship related to the distance sensor 2 is not established, the traveling speed V of the forklift 1
Is limited to the speed limit Va or less, and when it is determined that the proportional relationship of the distance sensor 4 is not established, the traveling speed V of the forklift 1 is limited to the speed limit Vb (<Va) or less. Therefore, the traveling speed V of the forklift 1 is decelerated and further stopped in accordance with the approach to the step D, so that the forklift 1 can be prevented from falling down, and when traveling at a place where the step D is present. The safety of can be secured.

Further, the distance sensors 2, 3 and 4 are the forks 2
Since it is attached so as to detect the distance to the measurement point on the traveling road surface F ahead of the tip of the fork 6, even if there is a step ahead of the tip of the fork 26, the traveling operation of the forklift 1 is prevented. It can be restricted and the safety can be improved. That is, when the distance sensors 2, 3 and 4 are arranged so as to detect the distance to the measurement point on the traveling road surface F that is relatively close to the vehicle body 22, it is determined that the proportional relationship is not established and there is a step D. Even if an attempt is made to stop the traveling operation after the vehicle is stopped, it is possible that the forklift 1 may not stop and fall from the step D because a certain stopping distance is required until it completely stops. In the form of, there is no such concern.

Although the three distance sensors 2, 3, 4 are provided in the above embodiment, the present invention is not limited to such a configuration, and for example, the two distance sensors 2, 2.
4 is attached, and when the proportional relationship of H1: H3 = L1: L3 is not established, the control device 5 causes the forklift 1 to move.
The traveling operation may be stopped or the traveling speed may be reduced. Further, the number of distance sensors is not limited to two or three, and it goes without saying that a large number of distance sensors may be provided to more finely control the traveling operation of the forklift 1. Further, although the distance sensors 2, 3 and 4 are provided on the outer surface of the mast 25 in the above embodiment, the mounting position of the distance sensor is not limited to the mast, and the load is placed on the fork 26. As long as the distance sensor can detect the distance to the measurement point on the traveling road surface F in the installed state, the vehicle body 22 and the head card 29 may be mounted at different height positions, for example.

Further, in the above-mentioned embodiment, the detection direction of the distance sensors 2, 3 and 4 is set to the front obliquely downward direction of the forklift 1, but the present invention is not limited to such a configuration, and the detection direction of the distance sensor may be changed. Accordingly, it is possible to prevent a fall from a step on the traveling road surface in that direction. For example, if the detection direction of the distance sensor is set diagonally downward to the side, it is possible to prevent falling from a step on the side of the forklift, and if the detection direction of the distance sensor is set diagonally downward to the rear, It is possible to prevent a fall from a step on the ground.

As an application example of the above-described embodiment, when the proportional relationship of the distance sensors 2 and 3 is established even when the proportional relationship of the distance sensor 4 is not established,
Instead of prohibiting the forward movement of the forklift 1, the traveling speed V of the forklift 1 is set to the speed limit Va (for example, 2k).
m / h) or less. Further, even when the proportional relationship related to the distance sensor 3 is not established, if the proportional relationship related to the distance sensors 2 and 4 is established, the traveling speed V of the forklift 1 is set to the speed limit V.
The configuration may be limited to a (for example, 2 km / h) or less.

Further, as another application example, the CPU 7 detects the detection distances L1, L2, L3 detected by the distance sensors 2, 3, 4 and the heights H1, H2, H3 stored in the memory 8. The relationship between H1: H2: H3 and L1: L2: L3 is not calculated based on the above, but the detection distances L1, L2, L3 detected by the distance sensors 2, 3, 4 and the memory 8 Based on the heights H1, H2, H3 stored in the table and the angle θ formed by the detection directions of the distance sensors 2, 3, 4 and the traveling road surface F, the vehicle travels from the mounting position of each distance sensor 2, 3, 4 The distance to the measurement point on the road surface (hereinafter referred to as the calculated distance) is derived by calculation, and it is determined whether or not the proportional relationship related to the derived calculated distance is established, and this proportional relationship is established. Controls running motion when not in use It may be. That is,
The calculated distances of the distance sensors 2, 3 and 4 are respectively S
1, S2, S3, as described above, when the forklift 1 travels on the flat traveling road surface F, H1: H2:
The proportional relationship of H3 = L1: L2: L3 is established, but at the same time, the proportional relationship of H1: H2: H3 = S1: S2: S3 is also established. Therefore, even if the control is performed using this proportional relationship, the same effect as that of the above-described embodiment can be obtained.

In the embodiment described above, the detection distance L
1, L2, L3 and the heights H1, H2, H3 are not proportionally established, the traveling motor 6 is controlled to limit the traveling operation. Alternatively, when the proportional relation is not established. A buzzer or a chime may be used to give an alarm to the operator. The buzzer and chime at this time are the alarm means in the present invention. By doing so, it is possible to notify the operator that the forklift 1 is approaching the step D, and it is possible to prevent the fall. Further, the alert to the operator by such an alarm may be combined with the limitation of the traveling operation as described above, and in this case, the safety can be further enhanced.

The scope of application of the present invention is not limited to the counterbalance type forklift, but the present invention can be applied to other types of forklifts and various cargo handling vehicles.

[0039]

According to the present invention, it is possible to prevent inconveniences such as the forklift falling from a step and improve the safety during traveling. In particular, by controlling the driving means so as to limit the traveling operation, even if the operator's driving skills are unskilled or the operator makes a mistake in driving, ensuring safety during traveling You can

[Brief description of drawings]

FIG. 1 is an external perspective view showing a simplified overall structure of a forklift according to the present embodiment.

FIG. 2 is an explanatory diagram schematically showing a side structure of a forklift according to the present embodiment.

FIG. 3 is a functional block diagram showing a simplified control system of the forklift according to the present embodiment.

FIG. 4 is an explanatory diagram schematically showing a traveling state of the forklift according to the present embodiment.

FIG. 5 is an external perspective view showing a simplified overall structure of a conventional forklift truck.

[Explanation of symbols]

1 Forklift (cargo handling vehicle) 2,3,4 Distance sensor (measurement means) 5 Control device (control means) 6 Traveling motor (drive means) 9 Speed sensor (speed detection means) 22 Vehicle body 26 forks H1 Distance sensor 2 mounting height H2 Distance sensor 3 mounting height H3 Distance sensor 4 mounting height Detection distance by L1 distance sensor 2 L2 Distance detected by the distance sensor 3 Detection distance by L3 distance sensor 4 F Forklift traveling road surface Road surface such as G truck D step

Claims (5)

[Claims] 1. A cargo-handling vehicle having a vehicle body for carrying out cargo-handling work and a drive means for driving and driving the vehicle body, wherein the vehicle body and a point on a road surface separated from the vehicle body by a predetermined distance. A plurality of measuring means for measuring the distance therebetween are provided so that the distances are different from each other, and the driving means is controlled so as to limit the traveling operation when the distance measured by each measuring means fluctuates. A cargo handling vehicle, characterized in that it is provided with control means for controlling. 2. A speed detecting means for detecting a traveling speed of the vehicle body is provided, and the control means drives the driving speed so that the traveling speed when traveling in a measuring direction of the measuring means is a predetermined value or less. The cargo handling vehicle according to claim 1, wherein the means controls the means. 3. The measuring means are provided at different height positions of the vehicle body so that the distance measuring directions are parallel to each other on the same plane perpendicular to the road surface. , Based on the relationship between the height of the mounting position of the measuring means and the distance measured by the measuring means,
The cargo handling vehicle according to claim 1, wherein the driving means is controlled. 4. A cargo-handling vehicle having a vehicle body for carrying out cargo-handling work and a drive means for driving and driving the vehicle body, wherein the vehicle body and a point on a road surface separated from the vehicle body by a predetermined distance. A plurality of measuring means for measuring the distance therebetween are provided so that the distances are different from each other, and when the distance measured by each measuring means fluctuates, an alarm is given to an operator who is on the vehicle body. A cargo-handling vehicle characterized by being provided with an alarm means for issuing. 5. A cargo-handling vehicle comprising a fork that can move up and down at a front portion of the vehicle body, wherein the measuring means measures the distance to a point on a road surface in front of a tip of the fork. The cargo handling vehicle according to any one of claims 1 to 4, wherein the cargo handling vehicle is provided as follows.